Growth of Crystals from Molten Crosslinked Oriented Polyethylene

Abstract
The growth of crystals from the melt in oriented, crosslinked polyethylene was studied by x‐ray diffraction and birefringence as a function of orientation. It was found that for samples elongated more than about 200%, the crystals grow with their c axes parallel to the stretching direction. At elongations less than 200%, there is a rather abrupt transition to a mode of growth in which the b axis is perpendicular to the stretching direction with a tendency for the a axis to be aligned parallel to this direction. An interpretation is made in terms of the folded‐chain concept of crystal structure.